<!doctype html>
<html lang="zh-CN">

<head>
    <meta charset="UTF-8">
    <title>左栏固定宽度，右栏自适应之绝对定位法</title>
    <style type="text/css">
    body {
        margin: 0;
    }
    
    #nav {
        width: 230px;
        height: 100%;
        background: #ccc;
        position: absolute;
    }
    
    #main {
        height: 600px;
        margin-left: 230px;
        background: #0099ff;
    }
    </style>
</head>

<body>
    <div id="container">
        <div id="nav">
            左栏
        </div>
        <div id="main">
            右栏
        </div>
    </div>
</body>

</html>
